Process of carbonating lead oxid.



F. H- SHARPE.

PROCESS OF CARBONATING LEAD 0x10.

APPLICATlON FILED JULY 2| |9l5| 1 196 595, Patented Au. 29, 1916.

Z SHEETS-SHEET I.

F. H. SHARPE.

PROCESS OF CARBONATING LEAD oxm.

APPLICATION FILED JULYI2,1915.

Patented Aug. 29, 1916.

2 SHEETS-SHEET Z.

FREDERICK HERBERT SHARZPE, F LIVERBOOL, ENGLAND.

PROCESS OF CARBONATING LEAD OXID.

masses.

Specificatiers Patent. Patgnt fl Aug. 29" 19116 Application filed July 12, 1915. Serial No. 39,448.

To all whom it may concern:

Be it known that I, FREDERICK HERBERT SHARPE, a subject of the King of Great Britain, residing in Liverpool, England, have invented a certain new and useful Improved Process for Carbonating Lead Oxid, of

which the following is a specification;

The process of making white lead by passing carbon dioxid or a mixture of this gas passes through the apparatus without being utilized. -This arisesinpart from-the high specific gravity of the lead oxid, which causes it to settle very quickly and in general the only way found practicable up to the present to meet the difficulty has been to vigorously stir the mixture mechanically.

This is, howeverfcostly. Another solution of the difliculty is that described in the specification of my prior United States Patent No. 1,088,460, in which as applied to the continuous manufacture of white lead, a series of vessels is used through which the liquid with its suspended matter is passedconsecutively and the gas is forced simply under pressure through the mixture in each vessel in turn. Experience with this process has shown that carbonation may vary in the different vessels and has suggested to the applicant that with a suitably constructed and arranged vesselthe carbonation process might be carried out in one vessel and the mixture kept efliciently stirred without the use of any mechanical means for thepurpose.

Other main objects which desire to accomplish by this invention are, to use ordi nary commercial or unfused lead oxid containing either free metallic lead orn'o metallic lead which it has been thought impossible to use in a single vat process becauseof the metallic lead which has been left uncar bonated, to carbonate continuously, and to utilize carbonic acid gas of varying strengths.

2 The present invention to this end com.-

prises a process for the manufacture of white lead in a single vat wherein lead oxld suspended in water containing an assistant is charged into the vat and carbon dioxid contamlng gas such as carbon dioxid alone or carbon dioxid mixed with another gas or other gases, is introduced'into the vat at or near the bottom in such a manner as to prevent settlemegt of the white lead and to cause thorough and etficient contact between the gas, the solid and the liquid.

The invention will be described with reference to the accompanying drawings.

Figure 1 is a vertical section through a Vat for carbonating lead oxid constructed according to the invention. Fig. 2 is a section on line 22 of Fig. l drawn to an enlarged scale. Fig. 3 is an elevation with part shown in section through another arrangement of vat. Fig. 4: is a section on line 44 of Fig. 3. Fig. 5 is a detail view showing one of the gas supply pipes disconnected. Fig. 6 is another detail view showing one of the jet cleaning plungers. Fig. 7 is a horizontal section on line 7 -7 of Fig. 3 showing a baflie ring. Fig. 8 is a partial elevation on line 8--8 of Fig. 7.

The mixture of lead oxid, water and a small proportion of acetic acid is run into the vat a, which preferably tapers inwardly toward the bottom through a cock 6. The carbonating gas which may be substantially pure carbon dioxid or fuel gases, for example, is pumped through a pipe 0, the delivery end of which is provided with a bellmouthed extension (Z directed toward the spherically curved bottom of the vat and situated. Within a short distance thereof. Close to the said delivery end,there project at right angles to the axis of the pipe four short curved horizontal pipes 0, also bellmouthed. The cross sectional areas of these four pipes at their junction with pipe 0 and the cross sectional area of the extension d", at its junction with pipe 0, .are together preferably slightly less than the cross sectional area of pipe e, so as to insure that there shall always be an excess pressure in pipe 0.

When the gas has been passed into the vat for some time a sample of the contents is removed through the test cock f and when such a sample shows that the lead oxid has been carbonated tothe desired degree, cock 9 is opened, whereupon the pressure of gas in the vat expels the liquid and solid contents. Cock 9 is now closed and more mixof gas being continued the while, so that the process may be said to be practically continuous.

5 a The blow-off valve k may be loaded to give any desired pressure within the vessel. Working under pressure is not essential but has the advantage that it aids the intimate contact of the gas with the mixture and prevents the excessive frothing which would occur in an open vessel.

If the quantity-of metallic lead in the oxid be abnormally large, air may be forced rthrough a separate opening in the vat so as to insure the oxidation of this'lead which might otherwise escape carbonation owing to insufliciency of the accidental oxygen the carbonatinggases.

Should apparatus such as that above described be allowed to stand for any reason, any leadoxid in the vat at once settles to the bottom and may have a tendency to choke the gas delivery, jets d and e, in which case it is necessary to remove the pipe 0 and the jets to clear them, the apparatus at the same time. being putout of use. The arrangement shown iii-Figs. 3 to 6 has been designed to obviate such a difliculty. The vat a is preferably similar in shape to that shown in Fig. 1,that is to say it is constructed tapering inwardly toward the bottom so that the lower portion a of the vat is of more or less conical shape and the actual bottom 7c of the vat is preferably made of comparatively very small size and slightly domed or conical as shown so as to throw anything falling on it down to the edges. At or near the bottom of the vat are arranged one or "more jets 6 introduced through thewalls ofthe'vat and directed more or less tangentially to said walls. Preferably, the direction is slightly more toward the center of the vat than the true tangential direction. The direction of the jets may also if desired be slightly downward toward the bottom of the vat.

Where one jet c'is used the lower portion a of the vat may be carried more nearly to a point and the area of the jet maybe made greater than the area of the actual bottom of the vat. 7 It is,- however, preferable'to employ a plurality of jets e as shown, because by this means the agitation of the material is more readily produced and maintained 5 and it is possible as hereinafter described to clean one jet while the others are continuously in operation. v Each of the "ets e isprovided'with a preferably full bore .cock 1 adjacent to'it,

. by which it can be shut off, and with a removable connecting pipe m (see Fig. 5) removably attached beyond the'cock 1 by which it is connected with the main'gas supply n. A cock nis also provided between the main supply 11, and each of the pipesm so arranged that the gas can be shut ofi from each pipe m individually to permit of its being disconnected and removed without interfering with the supply to the other pipes. Each pipe m is preferably made in two sectionsas shown with a non-return valve m arranged between them, to prevent any back pressure in the vat forcing the material in the vat back into or along them.

When it is desired to clean or inspect one of the jets c or its connecting pipe m, the cooks l and at corresponding are closed and the pipe m is disconnected. It can then be inspected and cleaned, its two-separate sections being disconnected from the'non-return valve m if found necessary. A plug is then inserted in the-bore of the cock Z,

the cock is opened and the plug is pushed into the vat to clean out the jet and then withdrawn, the cock Z being closed again,

before the plug is finally removed. Or, as,

The vat is provided with a cock g by which the contents may be evacuated and may be provided with a second cock p at the bottom by which any sediment collected in the bottom may be,removed from time to time.

In operation, after the vat'has been filled and the gas has been turned on, a rapid vertical movement is "set up in the vat owing to the direction of flow ofthe gas under pressure through the jets. The gas at the same time tends to rise up the sides of the vat passing around and around them more.

or less in a helical direction. At the same time the oxid of lead-which is thrown to, the.

sides by the centrifugal action tends to fall so thatit is brought into intimate contact with the rising gas. A more'or less general circulation of the liquid is also produced upward along the sides of the vat and downward-in the more quiescent center of the vat. 0

In order to increase the agitation and prevent too regular a circulation of the liquid and also to more efiiciently use up the gas, one or more circular, preferably downwardly inclined bafiies r (see Figs. 3, 7 and 8) may be arranged in the upper part of the vat. Such baflles 1' may extend almost around the vat leaving a narrow space 8 between the ends which .1s covered over with an angle plate t projecting outward toward the center ofthe vat. Such baflles trap a portion of the rising gaswhich is led ineaeet a through the space 8 and the gable t toward the center of the-vat and rises against the downwardly circulating liquid. 2

One or more test cocks f are provided in the side of the vat.

When the carbonation is completed, the cock 9 is opened, the contents being 'forced out by this cock under the pressure of gas in the vat, the gas inlet valves being left open while the vat is evacuated. Directly the vat is emptied the cock 9 is closed and the new material is fed into the vat without shutting oil the gas supply. In this way, agitation and carbonatlon of the new material as it is added begins immediately so that carbonation is continuous and no time being allowed for standing no settlement can take place in the vat.

A blow-ofi' valve fit for regulating the pressure in the vat may be employed with reference to Fi 1 and 2.

The gas passmg from the vat may be allowed to escape to the atmosphere, or if of suflicient strength it may be passed through a second vat, but when this 1s done there is no other connection between the vats, the complete process of carbonation taking place in a single vat.

The apparatus is not claimed herein, but is reserved to form the subject-matter of a divisional a plication.

Having t us described my invention and the best means I know for carrying the sameinto practical effect I claim:-

1. A single' vat process for the manufac ture of white lead, in which lead oxid suspended in water in conjunction with an assistant is introduced into a closed vat and carbon dioxid containing gas-is introduced into the vat at or near the bottom and with a swirling motion so as to prevent settlement of the solid material and to cause 1 thorough and efficient contact between the gas, the solid and the liquid.

2. A single vat process for the manufacture of white lead, in which lead oxid suspended in water in conjunction with an assistant is introduced into a closed vat andcarbcn dioxid containing gas is intro- Y and its suspended lead oxid.

more or less helical direction up the sides,

at the same time giving a swirling movement to the water and its suspended lead ture of white lead,'in which lead oxid sus- "pended in water in conjunction with an assistant is introduced into a closed vat and carbon dioxid containing as is introduced into the vat so as to cause t e material therein to swirl upwardly and outwardly against a conical-wall in the lower part of the vat and cause a downward fiflow of material in the middle of the vat.

5. Asjingle vat process for the manufactureof white lead, in which lead oxid suspended in water in conjunction with an assistant is introduced into a closed'vat and carbon dioxid containing gas is introduced a more or less tangentially into the vat at or near its bottom and tends to rise in a more or less helical direction up the sides, at the same time giving a swirling movement .to the water. and its suspended lead oxid, a portion of the gas as it rises being deflected toward the center of the vat tocause it to rise against the downward flow 6. A single vat process for the manuifacture of white lead, in which leadoxid suspended in waterin con unction with an assistant is introduced'into a closed vat and carbon dioxid containing gas is introduced througha plurality of jets more or less tangentially into the vat at or near its bottom. In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FREDERICK HERBERT SHARPE. v

.Witnesses:

Gno. W. EDWARDS, 310mm; W. Gmmn'r.

of water 

